/// <summary>
/// Same as <see cref="EvaluateAndDescribeAsync(IRStackFrame, string, string, REvaluationResultProperties, string, CancellationToken)"/>,
/// but uses <see langword="null"/> for <c>name</c>.
/// </summary>
public static Task <IRValueInfo> EvaluateAndDescribeAsync(
this IRStackFrame frame,
string expression,
REvaluationResultProperties properties,
string repr,
CancellationToken cancellationToken = default(CancellationToken)
) =>
frame.EvaluateAndDescribeAsync(expression, null, properties, repr, cancellationToken);
/// <summary>
/// Produces an object describing this frame's environment. <see cref="REvaluationResultInfoExtensions.DescribeChildrenAsync"/>
/// method can then be used to retrieve the variables in the frame.
/// </summary>
/// <param name="properties">
/// Which properties of the returned object should be provided. Note that it should include at least the following flags
/// argument value in order for <see cref="REvaluationResultInfoExtensions.DescribeChildrenAsync"/> to be working.
/// </param>
/// <remarks>
/// <para>
/// There is no guarantee that the returned evaluation result is <see cref="IRValueInfo"/>. Retrieving the frame environment involves
/// evaluating <see cref="EnvironmentExpression"/>, and like any evaluation, it can fail. Caller should check for <see cref="IRErrorInfo"/>
/// and handle it accordingly. However, it is never <see cref="IRPromiseInfo"/> or <see cref="IRActiveBindingInfo"/>.
/// </para>
/// <para>
/// If this method is called on a stale frame (i.e if call stack has changed since the <see cref="RSessionExtensions.TracebackAsync"/>
/// call that produced this frame), the result is undefined, and can be an error result, or contain unrelated data.
/// </para>
/// </remarks>
public static Task <IRValueInfo> DescribeEnvironmentAsync(
this IRStackFrame frame,
REvaluationResultProperties properties,
CancellationToken cancellationToken = default(CancellationToken)
)
{
properties |= ExpressionProperty | LengthProperty | AttributeCountProperty | FlagsProperty;
return(frame.EvaluateAndDescribeAsync("base::environment()", properties, null, cancellationToken));
}
